That makes sense.
I'm not sure how to articulate this, but it seems to me that there is some relationship between time to complete conversion and the amount of enzymes. Maybe it's only in instances where there are too few enzymes, because I have heard of mashes that have very low levels of enzymes that will take hours to reach conversion.
Think of one guy chopping down trees. Let's say he can chop down one tree an hour. It will take him 100 hours to cut down 100 trees. But if you have 10 guys, they can cut down 100 trees in 10 hours. But once you get over 100 guys you're probably not going to get faster than one hour to cut down the 100 trees.
Now, I don't know if this applies to enzymes working on sugars. But that's how I think about it from John Palmer's trees and branches analogy.